Voyager 1 and Voyager 2 at Saturn

Updated October 19, 2026 · 6 min read

Voyager 1 and Voyager 2 flew past Saturn in November 1980 and August 1981, nine months apart. Voyager 1 made its closest approach on 12 November 1980 and studied Titan from about 6,500 km, revealing a thick nitrogen atmosphere. Voyager 2 passed on 26 August 1981 and then used Saturn's gravity to continue to Uranus and Neptune. Together they turned Saturn's rings into a world of thousands of ringlets, spokes and shepherd moons.

A once-in-176-years alignment

In the late 1970s, Jupiter, Saturn, Uranus and Neptune lined up so that a single spacecraft could visit all four using gravity assists, an opportunity that recurs only about every 176 years. NASA built two identical three-axis-stabilized spacecraft, each about 825 kg at launch, with television cameras on a steerable scan platform, infrared and ultraviolet spectrometers, a photopolarimeter, magnetometers, particle detectors and a radio system that doubled as a science instrument. Each was powered by three radioisotope thermoelectric generators.

Voyager 2 launched first but on a slower path; Voyager 1 overtook it and arrived at both Jupiter and Saturn first, hence the numbering.

Voyager 1: Titan and a farewell to the ecliptic

The flight team had a choice for Voyager 1. It could pass close to Titan, the only moon then known to have a substantial atmosphere, or it could stay on a path toward Pluto. Titan won. On 12 November 1980, the spacecraft passed about 6,500 km from the moon and sent radio signals through its atmosphere as it slipped behind it.

The result was a landmark in Titan science: an atmosphere made mostly of nitrogen, with methane as a minor component, a surface pressure of about 1.5 bar (later refined by Huygens to 1.45 bar) and a temperature near -180 °C. An opaque orange haze of organic molecules hid the surface entirely, and researchers began to speculate about lakes or oceans of liquid hydrocarbons. Cassini confirmed lakes and seas a quarter-century later.

The Titan flyby bent Voyager 1's trajectory sharply north of the plane of the planets, ending its planetary tour. Hours later, it made its closest approach to Saturn itself, about 124,000 km above the clouds.

Voyager 2: the rings up close and the road to Uranus

Voyager 2 benefited from its twin's experience. Its sequences were tuned to follow up Voyager 1's surprises, and its approach geometry was chosen to keep it on course for Uranus. After the closest approach on 26 August 1981, the scan platform jammed in the horizontal direction as the spacecraft emerged from behind Saturn, and some planned observations were lost. Engineers recovered partial motion within days, and the lessons learned shaped operations at Uranus and Neptune.

One of Voyager 2's most precise ring experiments was a stellar occultation: the photopolarimeter watched the star delta Scorpii flicker as the rings passed in front of it, mapping structure at scales of a few hundred meters.

What the Voyagers discovered

The rings

• Thousands of ringlets. The broad A, B and C rings resolved into innumerable narrow bands, and even the Cassini Division proved to contain faint ringlets.
• Spokes. Dark, wedge-shaped features sweeping across the B ring and rotating with the planet's magnetic field rather than in step with the ring particles, now attributed to electrostatically levitated dust. See ring spokes.
• A braided F ring. Voyager 1 photographed knots, kinks and apparent braids, and found two small moons, Prometheus and Pandora, on either side of it: the classic shepherd moons.
• New small moons. Atlas, at the outer edge of the A ring, joined Prometheus and Pandora. A later re-examination of Voyager 2 images in 1990 also revealed Pan, inside the Encke Gap.

The planet

The Voyagers measured equatorial winds of about 500 m/s (1,800 km/h), among the fastest in the Solar System, and timed the radio emissions that gave the long-used rotation period of 10 h 39 min 22 s. Later work showed that this radio period drifts and does not track the deep interior; the modern estimate from ring seismology is about 10 h 33 min (see Saturn's rotation). Voyager images of the north pole also contained the first glimpse of the hexagon, identified in the data later in the 1980s.

The icy moons

Voyager provided the first maps of the mid-sized moons: the giant Herschel crater on Mimas, the bright and smooth plains of Enceladus that hinted at recent resurfacing, the long canyon of Ithaca Chasma on Tethys, the wispy streaks on Dione, the tumbling sponge-like Hyperion and the black-and-white contrast of Iapetus.

After Saturn

On 14 February 1990, Voyager 1 turned its camera back to make a family portrait of the Solar System, including Saturn and the famous Pale Blue Dot image of Earth. Voyager 1 crossed the heliopause into interstellar space in August 2012 and Voyager 2 in November 2018. In the mid-2020s, both were still transmitting, with instruments switched off one by one to save their dwindling power. Voyager 1 reaches about one light-day from Earth around late 2026.

Both spacecraft carry a Golden Record with sounds, music and images of Earth. The flybys set the scientific agenda for Cassini-Huygens, which was formally proposed in the 1980s largely on the strength of Voyager's questions.

Sources

• NASA JPL: Voyager
• NASA Science: Voyager 1
• Smith, B. A. et al., "Encounter with Saturn: Voyager 1 imaging science results", Science 212, 1981
• Smith, B. A. et al., "A new look at the Saturn system: the Voyager 2 images", Science 215, 1982